How long should one freeze precip for maximum yield. I usually do it for 8-12 hours.... but would 24-48 hours of freeze yield more or am I leaving it long enough? My freezer is real f'ing cold, it can make a warm can of pop ice cold in 45 minutes

I tryed leaving it in for longer and no I think it sort of stop percing crystals. What I like to do is re use that naptha and repeat some pulls the after I cannot get any more to percip I evap the last leaving a yellow oily gunk. Rest of the spice left behind I love it!

-20 Celsius or lower I believe is the prime temperature from what SWIM has heard.
By the 48hr mark, all the crystals should have formed..
Even if you are in a hurry to get your spice, you can always grab the crystals and either re-pull or just stick the naphtha right back in.
Evaporating some of the naphtha pre-freezer helps saturate the solvent for a quicker crystallization. (Wastes some solvent though)

8-12hrs isn't anywhere near long enough. try 48-72hrs.

Not necessarily. Once in a hurry swim reduced her NP solvent to ~1/7th of the original volume and put the beaker in a freezer for less than 3 hrs. The spice chrashed out yielding 1.2%. Subsequent evaporation of naphta yielded only 0.1% more.

On numerous occasions swim collected all spice after 6 hrs or less.

It seems that for fast precipitation 2 things are important:

- Maximum reduction. For swim usually it is 10 ml / 1 g or less.
- Very cold freezer.

I just waited 16 hours and got a .9% yield on my first pull!!! Trying to refreeze whats left of the naphtha to see if anythings left but I am very impressed by this source for quality dye.

Yeah, that is great yield.



It's a good idea to reduce it first, because naphta left from previous freeze precipitation is far from being super-saturated and may yield nothing.

It is even better to completely evaporate it and add the resulting goo to your basified solution during some future extractions.

I had a thought; Is it better when you first begin to siphon off your solvent layer for freeze-precip, would it be more beneficial/increase yield if the pyrex/baking dish you throw the siphoned solvent into IF it was already cold. This would cool the solvent immediately, probably slowing the pre-evaporation step. Any thoughts?

Sure, that would probably help to get the alkaloids out of the solvent sooner, but I don't believe it would increase yields overall. It might get you more if you only had, say, two hours of freezing time for some reason, but then you wouldn't necessarily be getting everything out of the solvent.

The key is to saturate or super-saturate the solvent with alkaloids (warmer solvent is often used because it can typically hold more DMT than colder solvent), then cool it down as much as possible to lower its solvency and crash out the goodies. I think the important variables to take into account with respect to speeding up a freeze precipitation are the length of time it takes to get the solvent to the coldest temperature you can achieve and how much DMT is in the solvent to begin with.

If you have a lot of solvent it'll probably take longer to cool it all down, so a full freeze-precipitation will take longer to achieve. Evaporating can help here, but might also add just as much time to the process as cooling down the original larger quantity. Minimizing evaporation and reusing your solvents also means less toxins vaporizing into the air and less petrochems being extracted from the earth to be distilled in those nasty refineries.

As the ratio of DMT:solvent is increased, you'll find that more alkaloids crash out when your solvent finally reaches that coldest temperature. Evaporation would also help in raising that ratio, but using the right amount of solvent for the amount of spice you expect to extract is probably almost as effective and less wasteful.

My preference (in case you hadn't guessed :wink would be to conserve the solvent for reuse rather than evaporate it off. That approach may involve a slight decrease in total yield, but I believe the benefits outweigh the downsides. Everyone has an opinion on this debate and many differ significantly, so please feel free to do some experimentation and settle on a technique that you feel is appropriate for your purposes.

-JM

Someone correct me if this is off, but it seems to me that once the NPS reaches the lowest temperature in a good freezer (-18C or less), all that will precipitate should have done so. Meaning within a few hours with 500ml of NPS.

With a warmer freezer, perhaps there is more of a time curve (or not?)?

Again, this is just a guess, but seems to fit my understanding of the physics behind it.

JBArk

I totally agree, but I find that it can take more than a few hours for the spice to stop dropping out. Sometimes 24+. Maybe it's that we're dealing with different freezer temperatures or solvents that are hotter/colder when added to the freezer. Either way, I concur that all the spice that's going to precipitate out will have done so once your solvent reaches the coldest temperature you can achieve in your freezer. At least that matches up with my understanding of the physics/chemistry involved.

I think it really depends on the saturation of the NP. I've done pulls towards the end of an extraction that had no crystals after 24 hours, barely any after 48 hours, yet on the 3rd-4th day had some beautiful crystal clusters.

Regardless I reuse all of my NP. so if you don't precip it all out now you can get it later.

Much thanks J. I get a better grasp on this life form all the time.

Hyper: Are you leaving the solvent for the precip step in that long (3-4 days)?

If there is very little dmt in your solvent, yes id leave it for a good 3 days. A normal pull though I have nice crystal formation after 12 hours but seems best at 48.

Swim never works with more than 100 ml of NPS during freeze-precip (usually around 20 ml) but once she tested how long it takes the solvent to reach thermal equilibrium with the freezer chamber. So, for 100 ml it takes less than an hour. depending on how well the beaker contacts the chamber walls and whatever stuff is in there already.

Precipitation takes much longer and continues quite some time after the equilibrium is reached. Most probably the spice concentration in NPS falls exponentially to a certain limit specific for a certain temp. We can only get more spice from this NPS by either increasing concentration or by decreasing the temp.



Another good way to increase your solvent extraction efficiency is to use many small pulls instead of fewer big ones.

That would do no harm, but if you reduce your NPS so that it will get cloudy at ~60C, all spice will crash out in less than 6 hrs.